A traditional wireless access network consists of a number of base stations (access points) connected to a centralized controller (radio network controller/base station controller) using wired links (copper, co-axial cable, fiber). The radio network controllers are connected back to circuit-switches or packet-data routers which in turn connect to the wired telecommunications infrastructure (the core network). This traditional, hierarchical network is shown in FIG. 1.
In typical base station deployments in current networks, a wired connection is usually required from each base station to the controller and then onwards to the core network. In the vast majority of cases, these wired links are T1, E1, Ethernet or fiber links. In some rare cases, specialized dedicated line-of-sight microwave links are employed that use separate spectrum. Implementation of such dedicated backhaul connections is usually expensive. There may also be pairs of base stations in an existing network for which a dedicated backhaul connection can not be reliably or economically implemented. It is therefore worth considering alternative approaches to reducing backhaul costs. One such alternative is to somehow provision wireless backhaul links between the base stations themselves and thereby provide the backhaul communications path. Furthermore, it would be desirable not to dedicate separate spectrum and specialized equipment for such backhaul.
In the case of fault isolation and trouble-shooting of base-stations, techniques in current cellular networks rely on the ability of the network operators to correlate information from many diverse sources. Quite often, the back-haul connection is leased from third-party service providers. Many times, when a lack of service is detected from a base-station, the root-cause cannot be clearly isolated to the wired network or the base-station RF chain for several hours, if not longer. There is no other mechanism available today to log-in to affected base-stations remotely when a backhaul may be malfunctioning. A site visit is required by a technician to confirm or rule out a mal-functioning base-station. This very expensive site visit could be avoided if another mechanism were made available to diagnose base-stations remotely.
Further, the actual numbers of infrastructure nodes (base stations or access points) is likely to increase by a few orders of magnitude. Typically, each of the large service provider networks today consist of in excess of 50,000 cells sites at which base stations are located. It is not unrealistic to expect such numbers to grow by a factor of 100 to about 5 million. Such large number of base stations will be needed to ensure truly ubiquitous data coverage. It is also likely that many of these new access points cannot be easily supported with a wired backhaul to the core network.